425: TuHURA Biosciences and Kintara Therapeutics Announce Positive Phase 1b Trial Results for IFx-2.0 in Checkpoint Inhibitor Resistant Cancers

TuHURA Biosciences and Kintara Therapeutics reported positive results from a Phase 1b trial of IFx-2.0, a personalized cancer vaccine, showing promising efficacy in patients with advanced Merkel Cell Carcinoma and Cutaneous Squamous Cell Carcinoma resistant to checkpoint inhibitors.

Summary

• TuHURA Biosciences and Kintara Therapeutics announced positive results from a Phase 1b clinical trial evaluating IFx-2.0 in patients with advanced or metastatic Merkel Cell Carcinoma (MCC) and Cutaneous Squamous Cell Carcinoma (cSCC) who were resistant to immune checkpoint inhibitor (ICI) therapy.
• The trial showed that IFx-2.0 was safe and well-tolerated at once-weekly dosing for three weeks.
• In ICI-naive patients with advanced MCC who failed to respond to pembrolizumab or avelumab, 80% achieved a durable Complete Response (CR), pathologic CR, or Partial Response (PR) following IFx-2.0 therapy and rechallenge with an anti-PD(L)-1 checkpoint inhibitor.
• The average duration of response was 25 months, with two responses ongoing at 19 and 23 months.
• The Phase 3 trial will examine IFx-2.0 as an adjunctive therapy with Keytruda (pembrolizumab, an anti-PD-1 agent) to improve tumor overall response rates when compared to Keytruda plus placebo in first line treatment of ICI nave patients with advanced or metastatic MCC.
• This Phase 3 trial is expected to begin enrollment in 2H-2024 under the FDAs Accelerated Approval Pathway.
• TuHURA and Kintara have entered into a definitive agreement for an all-stock transaction to form a company focused on advancing TuHURAs personalized cancer vaccine(s) and first-in-class bi-functional Antibody Drug Conjugates (ADCs).
• The combined company is expected to operate under the name TuHURA Biosciences, Inc. and to trade on The Nasdaq Capital Market under the ticker HURA.
• The transaction is subject to customary closing conditions, including stockholder approval of both companies, and is expected to close in the third quarter of 2024.

Sentiment

Score: 8

Explanation: The document presents positive clinical trial results and a strategic merger, indicating a favorable outlook for the companies involved. The high response rate in a difficult-to-treat patient population is particularly encouraging.

Positives

• IFx-2.0 showed a promising efficacy signal in overcoming primary resistance to anti-PD(L)-1 therapy.
• The Phase 1b study met its primary safety objective, demonstrating that IFx-2.0 is safe and well-tolerated.
• The planned Phase 3 trial has the potential to provide a new treatment option for patients with advanced or metastatic MCC.
• The merger of TuHURA and Kintara could create a stronger company with a more diversified oncology pipeline.

Risks

• The merger is subject to customary closing conditions, including stockholder approval, and may not be completed.
• The Phase 3 trial may not be successful, and IFx-2.0 may not receive regulatory approval.
• The combined company may face challenges in integrating the two businesses and advancing its pipeline.
• Forward-looking statements are subject to risks and uncertainties, and actual results could differ materially.

Future Outlook

The combined company will focus on advancing TuHURAs personalized cancer vaccine(s) and first-in-class bi-functional Antibody Drug Conjugates (ADCs). The Phase 3 trial is expected to begin enrollment in 2H-2024 under the FDAs Accelerated Approval Pathway. The transaction is expected to close in the third quarter of 2024.

Management Comments

• Dr. James Bianco, Chief Executive Officer of TuHURA, commented that IFx-2.0 demonstrated the ability to overcome resistance to ICI in 63% of patients with advanced MCC, even in patients who progressed on both anti-PD1 therapy followed by anti-PD1/CTLA-4 combination therapy.

Industry Context

The announcement is relevant to the immuno-oncology space, where overcoming resistance to checkpoint inhibitors is a major challenge. The positive results for IFx-2.0 suggest a potential new approach to address this resistance, which could be significant for patients with advanced MCC and cSCC.

Comparison to Industry Standards

• The reported 80% objective response rate in ICI-naive MCC patients is notably high compared to typical outcomes with checkpoint inhibitors alone in resistant populations.
• For example, single-agent anti-PD-1 therapies like pembrolizumab and avelumab often show lower response rates in patients who have already progressed on these agents.
• The planned Phase 3 trial design, comparing Keytruda plus IFx-2.0 to Keytruda plus placebo, aligns with standard regulatory pathways for seeking accelerated approval in oncology.

Stakeholder Impact

• Shareholders of both Kintara and TuHURA will be impacted by the proposed merger, requiring their approval.
• Patients with advanced MCC and cSCC could benefit from the development of IFx-2.0 as a new treatment option.
• Employees of both companies may be affected by the integration of the two businesses.

Next Steps

• Initiate the Phase 3 registration trial of IFx-2.0 with Keytruda in the second half of 2024.
• Obtain stockholder approval for the proposed merger.
• Close the merger transaction in the third quarter of 2024.
• Advance the development of TuHURAs personalized cancer vaccines and ADCs.

Key Dates